This invention relates generally to telecommunication devices for the deaf.
Hearing-impaired people communicate over telephone lines by using telecommunication devices for the deaf (TDDs), also known as teletypewriters (TTYs). TDDs resemble portable laptop computers, except that their displays are typically limited to one or two lines of alphanumeric text. TDDs communicate on telephone lines via a standard Baudot communications protocol (asynchronous, no carrier, half-duplex, frequency-shift-keying, 45.45 baud).
Until approximately a decade ago, most TDDs came equipped with acoustic couplers, resembling suction cups, into which the handsets of standard telephones are placed and the TDDs communicate through the handsets"" microphone and speaker. Nowadays, the majority of TDDs plug directly into wall telephone jacks, and interestingly only the more expensive models also come equipped with acoustic couplers that allow them to be used in conjunction with telephone handsets.
Some users of TDDs wish to use mixed-mode TDD-and-voice communication. That is, they wish to use the TDD to communicate in one direction and to use voice to communicate in the other direction. For example, a person who is hard of hearing but still able to speak clearly may wish to receive via TDD and reply by voice. Conversely, a person who hears well but has trouble speaking may wish to receive voice from the other party and reply via TDD. People who wish to communicate in this mixed-mode fashion, as well as the people on the other end of these calls, must use TDDs that are equipped with acoustic couplers, and must continuously pop the telephone handset into and out of the TDD""s acoustic coupler in order to switch back-and-forth between TDD and voice communication. This is very awkward and disruptive.
This invention is directed to solving these problems and disadvantages of the prior art. According to one aspect of the invention, a telephone handset comprises an earpiece and a mouthpiece detachably attached to each other, thus allowing one of the earpiece and the mouthpiece when detached to be used by a human user for listening or talking, respectively, on a telephone call while simultaneously allowing the other of the earpiece and the mouthpiece to be used for receiving or transmitting, respectively, data with an acoustic couplerxe2x80x94the acoustic coupler of a TDD, for example. According to another aspect of the invention, a telephone handset comprises an earpiece, a mouthpiece, and a handle detachably attached at one end to the earpiece and at the other end to the mouthpiece, thus allowing one of the earpiece and the mouthpiece when detached to be used by a human user for listening or talking, respectively, on a telephone call while simultaneously allowing the other of the earpiece and the mouthpiece to be used for receiving or transmitting, respectively, data with an acoustic coupler.
A telephone handset according to the invention permits convenient use of the handset in both a standard mode of operation and in a hybrid TDD-and-voice mode of operation. The invention thus permits any user voice terminal that is equipped with the handset to be used as a mixed-mode terminal. When the detached earpiece is mounted to a head-clip, it further facilitates hands-free use of the handset in a receive-voice/transmit-TDD mode of operation that frees both of the user""s hands for typing on the TDD. When the earpiece is equipped with a device that automatically mutes the sidetone path when transmitting via TDD, the user will not hear the Baudot tones emitted by his or her TDD when typing.
These and other features and advantages of the invention will become more evident from the following detailed description of an illustrative embodiment of the invention considered together with the drawing.